Telephone-receiver



H. C. HARRISON. TELEPHONE RECEIVER. 5 APPLICATION FILED SEPT- IO. I918- Patented Nov. 15, 1921.

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H. C. HARRISON.

TELEPHONE RECEIVER. APPLICATION FILED SEPT- I0. 1918.

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SIZE- UNITED STATES PATENT OFFICE.

' HENRY C. HARRISON, OF NEW YORK, N. Y., ASSIGNOR TO WESTERN ELECTRIC OOM- PANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELE1HONE-REOEIVER.

Specification of Letters Patent. Patented NOV. 15, 1921;

Application filed September 10, 1918. Serial No. 253,356?

To all whom it may concern:

Be it known that I, HENRY G. HARRISON, a citizen of the United States, residing at New York, in the county of New York, State of New York, have invented certainnew and useful Improvements in Telephone-Receivers, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone receiv ers for general use in telephone or signaling circuits and has for its object to provide a receiver with an improved magnetic structure and one having its parts so proporltioned and arranged as to provide an instrument of high sensitivity in responding to feeble alternating currents such as those generated by the voicewaves impinging on a transmitter diaphragm. More specifically the object of the invention is to provide a telephone receiver having a balanced magnetic circuit arranged in such a manner as to operate efliciently and without causing undue distortion of the voice current wave forms. To attain this object the invention consists of certain new and novel features of construction as will be more fully described and particularly pointed out in the appended claims.

In the accompanying drawings, Figure 1 is a View partly in section of a watch case t pe of receiver embodying this invention;

ig. 2 is an enlarged view in perspective of the magnetic structure of the receiver shown in Fig. 1, a portion of the upper pole piece and the magnetic diaphragm being cut away to more clearly show the details of construction; Fig. 3 is a diagrammatic view of the magnetlc circuit of the receiver shown 1n- Fig. 1; Fig. 4 is a View partly in section of a slightly different form of receiver embodying this invention; Fig. 5 is an enlarged View of the magnetic structure and Fig. 6 is a diagrammatic view ofthe magnetic circuit of the receiver shown in Fig. 4; Fig. 7

is a view partly in section of another modification employing a permanent magnet; Fig. 8 isa sectional view of the receiver shown in Fig. 7 taken along the line 88 and looking in the direction of the small arrows; and Fig. 9 is a diagrammatic View showing the magnetic circuit of the receiver shown in Fig, 7.

eferrmg first to Figs. 1 to 3,, there is shown a receiver casing 10 of the customary watch case type, preferably made of hard rubber, and provided with a cap-piece 11 which is provided with screw threads adapted to engage similar threads on the casing member. The magnetic structure mounted within this casing comprises a lower member 12 which is secured to the base of the casing and an upper member 13 which is maintained in a certain position with respect to 12 by means of the threaded studs i l-14 and the lock nuts 15-15. The upper member 13 is provided with three pole pieces 16, 17 and 18. The middle pole piece 17 is equipped with a polarizing coil 19 and a talking coil 20 for the AC or talking currents. The lower member likewise is provided with three pole pieces 21,22 and 23. Upon the middle pole piece 22 there is likewise provided a polarizin coil 24 and a talking coil 25 for the AS or talking currents. Located equidistant between the upper and the lower pole pieces is the magnetic diaphragm 26 which is provided with extension portions 2727 whereby it is held in a fixed position which may be easily adjusted by means of the locknuts 28-28 threading on the studs 14-44:. Secured to the center of this diaphragm is the rod 29 which is also secured to the center of the main receiver diaphragm 30. The'polarizing coils are connected'in series and are so wound that with the current flow in the di rection indicated by the arrows the middle pole of the upper magnet is made a south pole and the two outer poles are made north poles, while on the lower member the middle pole is a north pole and the outer poles are south poles. The pole pieces positioned opposite each other are in each case of opposmg polarity. The talking windings 20 and 25 are likewise connected in series and in such a manner that current flowing through the windings in a given direction will make the two middle poles of one polarity while the outside Tpoles will all be of the opposite rent flowing through the talking windings follows the former in its excursions.

in the direction as designated, the operation of the receiver will be understoodby an examination of the magnetic circuits. There are two paths for the steady or polarizing flux, one extending from outer pole piece 16 across the gap to pole piece 21, middle pole piece 22, across the gap to middle pole piece 17, and back to north pole 16,.and the other from outer pole piece 18, across the gap to outer pole piece 23, to middle pole piece 22' across the gap to middle pole piece 17 and thence back to outer pole piece 18. The paths for the flux generated by current flowing in the talking windings with the direction of current as indicated are as follows:

1. From outer pole piece 16 across the gap to the diaphragm 26, thence across the gap to the middle pole piece 17 and back to outer pole piece 16. Y

'2. From outer pole piece 21 across the gap tothe diaphragm 26, thence across the gap to pole piece 22, and back to outer pole piece 21.

3. From pole piece 18 across the gap to diaphragm 26, thence across the gap to pole piece 17, and back to pole piece 18.

4. From outer pole piece 23, across the gap to diaphragm 26, thence across the gap to pole piece 22, and back to pole piece 23.

With the above paths for the polarizing or constant flux and the alternating flux at a given instant it will be .noted that the flux from the talking winding is in a direction to augment the constant flux from poles 16 and 18 to the diaphragm, and from the diaphragm to pole piece 17 and in a direction to oppose the constant flux flowing from pole pieces 21 and 23 to the diaphragm and from the diaphragm to pole piece 22. It will be thus seen that the effective flux between the upper pole pieces .and the dlaphnjagm is increased, whereas the flux flowing between the lower pole pieces and the magnetic diaphragm is diminished and the magnetic diaphragm is accordingl drawn toward theupper pole pieces. Wit

the current flowing through the talkingwindings in the opposite direction, the flux paths are such as to cause the diaphragm to'be drawn toward the lower pole pieces. Since the magnetic diaphragm 26 is rigidly secured to the main diaphragm 30 the latter \Vith no current flowing through the polarizing windings l9 and 24, and with an ideal adjustment the effects of current flowing through the talking windings 20 and 25 neutralize each other and hence there is no tendency for distortion of the voice currents.

Referring now to Figs. 4, 5 and 6,'there is shown a, mechanical construction similar to the one described above yet having a somewhat modified magnetic circuit. In this case the receiver is also polarized by magnetizing windings, the windings 31, 32, 33 and 34 being located on the outer pole pieces and arranged to provide the same popole, pole piece 40 is made a south pole,

pole piece 41 is made a south pole and pole piece 42 a north pole. The eflect of current flowing through the talking windings is such as to make the middle poles neutral. The paths for the' constant flux are the same as with the construction shown in Fig. 3. The paths for the alternating or talking flux under the conditions indicated will be as follows:

1. From outer pole 39, across the gap to diaphragm 45, through the diaphragm and across the gap to pole 42, and thence back to pole 39 through the upper member 46.

2. F mm the outer pole piece 40, across the gap to diaphragm 45, through the diaphragm and across the gap to outer pole 41, and thence back to pole 40'through lower member 47 It will thus beseen that the alternating flux will be in a direction to augment the constant flow of polarizing flux across the gaps from pole piece 39 to the diaphragm and from the diaphragm to pole 41, while the direction of the alternating flux across the gaps from pole 40 to the diaphragm and from the diaphragm to the pole 42, is such as to oppose the constant or polarizing flux. The diaphragm will therefore be rotated in a clockwise direction, one end approaching pole 39 and the other end approachingpole 41. With current flowing in the opposite direction through the talking winding, the direction of flux will be such as to cause the diaphragm to be rotated in the opposite or counter-clockwise direction. The magnetic diaphragm 45 is equipped with pivot extensions 4848 which engage suitable pivot holes in the blocks 4949. These blocks are adjustable, being secured in place by the nuts 5050, and the nuts in turn are threaded on the studs 5151. The upper and lower members 46 and 47, respectively, are also secured in place by the nuts 52-52 threading on the studs 51-51. One end of the diaphragm is provided with an extension 53 to which is rigidly secured a stein 54 and the other end of this stem is secured to a lever 55 which is pivoted at the bracket 56. The other end of this mean? diaphragm 45 are repeated in the main diaphragm {58. Under certain conditions it might be found desirable to dispense with the lever member 55, in which case the stem 54 would be connected directly to the main diaphragm ,58 in the manner shown in Fig.

1, the magnetic structure in this event being necessarily mounted at one side of the receiver casing. V p

In the modification shown in Figs.'7, 8 and 9, a semi-circular permanent magnet is provided with a pair of polar extensions 61-62 disposed at either end of the permanent magnet and extending in opposite directions, these extensions being secured to the magnet by means of the screws 63-63. Secured to the upper member 61 is the soft iron cup 64 in which. is mounted the coil 65 having a soft iron core 66. A similar cup-shaped member 67 is secured to the lower member 62 and is provided witha coil 68 wound about the core 69. The cups 64 and 67 are separated from each other by means of a pair of. shouldered non-magnetic rings 70 -71, between which is clamped the magnetic diaphragm 72. A stem 73 is connected at one end to the magnetic diaphragm 72 and at its other end to the main diaphragm 74, this stem projecting through suitable openings in the core 66, cup 64, and pole extension 61. Thus any vibrations of the magnetic diaphragm are reproduced in the main diaphragm. The coils 65 and 68 are connected together in such a manner as to make the middle poles of the same polar ity as a result of any current traversing the windings. The paths for the constant or polarizing flux Wlll in each case be directly acrossthe gap from one cup. member and its core to the other member and its core. The paths for the flux set up by the alternatifig currents will be as follows:

1. From core 66, across the gap to diaphragm 72, thence extending radially through the diaphragm and across the airgap to cup-member 64, and back to core 66.

2. From core 69, across the ga to diaphragm 7 2, radially through the diaphragm and across the air-gap to cup-member 67, and back to core 69.

Under this condition the flux generated by the voice currents is in a. direction to augment the constant flux passing across the air-gap from the pole 66 to the diaphragm and to oppose the constant flux passing from the diaphragm to pole 69.

The direction of flux between the diaphragm and ,the upper and lower cup members is such as to neutralize each other and moreover, the diaphragm at its outer edge is rigidly clamped against movement by the non-magnetic rings 70, 71. The center of the diaphragm is therefore drawn toward pole 66. In the same manner with current flowing through the windings in theopposite direction the center of the diaphragm would be drawn toward pole 69. Instead of employing the cup-shaped members 64: and 67 tilpolar extensions may be employed of the same type as shown in Figs. 2 and 5.

alternating current flux passes through the diaphragm longitudinally or in the plane of the-diaphragm, since the manner in which the windings are placed on the cores is such that any tendency for the polarizing flux to pass through the diaphragm longitudinally and to form. separate magnetic circuits on either side of the diaphragm, would result in equal and opposing magneto motive forces in the diaphragm. The polarizing flux, therefore, only passes through the dia' phragm transversely, as pointed out above in explaining the flux paths for the difi'erent structures. Consequently the diaphragm does not become saturated and bring about a loss in efiicie'ncy as would be the case if the polarizing flux were allowed to pass through the diaphragm longitudinally or in the plane of the diaphragm. Also in each of the structures disclosed, there is provided a low reluctance path for the alternating current flux. The magneticcircuits moreover, are balanced in such a manner as to prevent any distortion of the magnetic diaphragms and the .resulting undesirable quality of transmission. While these magnetic circuits have been disclosed in connection with the receivers of the ordinary watch case type, their advantages are such that they mlght very well be employed for other somewhat similar uses, such for example as sensitive alternating current relays or signaling devices and loud speaking receivers.

What is claimed is:

1. In a telephone receiver, a magnetic dia-, phragm, a set of three pole pieces oppositely disposed on either side of the diaphragm,

means for giving opposingpole pieces constant opposite polarities, and additional means for giving opposing pole pieces variable like polarities.

2. In a telephone receiver, a magnetic. diaphragm, a set of three pole pieces disposed on one side of the diaphragm and. opposed by a corresponding set of three pole pieces on the other side of the diaphragm, means for giving opposing pole pieces constant opposite polarities, and additional means for superimposing variable polarities of like sign upon opposing pole pieces.

3. In a telephone receiver, a magnetic diaphragm, a set of three ole pieces disposed on each side of the diaphragm and in opposite relation to each other, a magnetizing winding for each set of pole pieces, said magnetizing windings being so connected as to establish constant flux pathsbetween the opposing pole pieces on either side of the In all of the structures disclosed only the pole pieces so connected as to establish variable flux paths between the different pole pieces on the same side of the diaphragm.

4. In a' telephone receiver, a magnetic diaphragm, an odd number of pole pieces disposed on each, side of the diaphragm and separated therefrom by air-gaps, means for establishing constant flux paths across said air-gaps between opposing pole pieces, and additional means for establishingvariable flux paths between the pole pieces on each side of the diaphragm.

5. In a telephone receiver, a magnetic diaphragm, a set of three pole pieces oppositely disposed on either side of the diaphragm, means for constantly maintaining oppositely positioned pole pieces at opposite magnetic polarities, and additional means for superimposing on said pole pieces periodically variable magneto motive forces producing at any instant like polarities on said oppositely positioned pole pieces.

6. In a telephone receiver, a magnetic diaphragm, means, for producing a constant magneto motive force, means for producing a periodically varying magneto motive force, magnetic structures on opposite sides of the magnetic diaphragm, said magnetic structures and said diaphragm jointly affording a plurality of magnetic circuits for the flux produced by said constant magneto motive force and each of said magnetic structures and the diaphragm affording a plurality of independent magnetic circuits for the flux produced by said varying magneto motive forces.

7. In a telephone receiver, a casing, a cap portion therefor, a diaphragm clamped be tween said casing and cap, and a magnetic structure inclosed within said casing, said magnetic structure comprising a magnetic diaphragm rigidly connected to said first diaphragm, an odd number of magnetic pole pieces disposed on either side of said magnetic diaphragm and in opposite relation to each other, means for oppositely magnetizing opposing pole pieces, and additional means for magnetizing opposing pole pieces to the same polarity.

In witness whereof, I hereunto subscribe my name this 29th day of August A. D., 1918.

HENRY C. HARRISON. 

